The present invention relates generally to utility pole testing apparatus and more particularly to such apparatus which is specifically designed to test the soundness of metal or steel poles utilized by various public utilities for supporting street lights and the like.
There exist a wide variety of applications wherein elongated steel or metal poles are utilized to support cables and/or street lights or the like in elevated relationship to ground level. Typically these metal poles comprise elongated tapered hollow tubes having a generally square or rectangular mounting plate fixedly secured to the lower end thereof such as by welding. The metal plate is designed to be bolted or otherwise secured to a suitable mounting pad such as a concrete pad having suitable threaded members embedded therein. While these poles are typically well treated by various means to retard the corrosive action of the elements when manufactured, nevertheless many of these poles have been in use under extreme adverse environmental conditions for extended periods of time and hance the corrosive inhibitors have degraded to the point where such poles have become subject to corrosion. Most commonly this corrosion is initiated in the interior of the pole where moisture becomes trapped and is able to act on the exposed metal surfaces therein. Once this corrosion begins it is only a period of time before the pole becomes sufficiently weakened to the point where it is no longer able to support its intended load. Accordingly, various users of such poles have become increasingly concerned with detecting such poles which have suffered excessive deterioration in order to replace same before they create a dangerous condition.
While various types of apparatus have been developed in an effort to provide suitable means whereby this interior corrosion may be efficiently and easily detected, none of the apparatus thus far developed have proved to be totally satisfactory. Because such poles are often located in locations not easily accessible, it is particularly desirable that any such testing equipment be easily portable. Further, it is of critical importance that the testing apparatus be particularly well designed to provide repeatable accurate and positive indications of the soundness of such metal poles without significant reliance on operator interpretation of the test results so as to avoid the possibility of both excessively corroded poles not being replaced as well as replacement of poles still having a sufficiently long service life remaining. Also, it should be noted that such testing apparatus will typically be utilized by relatively unskilled personnel and may be subject to a less than desirable degree of care both in use and in transportation. Accordingly, such apparatus should be ruggedly constructed and relatively simple and easy to use.
The present apparatus accomplishes these objectives by providing a relatively simple, straightforward testing apparatus which may be easily utilized by any individual without requiring excessive training in the operation thereof. Further, because the testing apparatus of the present invention incorporates a relatively few number of parts and is simple and straightforward in its construction, it is well suited to provide consistent and repeatable indications of the soundness of such poles. The apparatus of the present invention incorporates a spring loaded piston having affixed to a forward end thereof a plunger having a suitable contoured conical forward end member which is designed to impact the outer surface of a metal utility pole. The spring loaded plunger is designed to be manually retracted into a cocked position whereupon the apparatus may be pressed against a pole to be tested and a trigger meachanism actuated thereby releasing the piston and plunger causing the conical projection to impact the outer surface of the pole. If the pole has suffered excessive corrosion to the extent where the wall thickness has deteriorated sufficiently to allow the conical projection to penetrate therethrough, the pole will be deemed to be unsafe and may thus be scheduled for replacement. If, however, the projection does not penetrate the surface at all or sufficiently, this will provide an indication the pole is presently sufficiently sound to endure further usage.
The testing apparatus of the present invention is not designed to provide an indication of the absolute strength of the wall of the pole being tested but rather is designed to provide an indication whether the wall thickness possesses a strength in excess of a predetermined minimum such that the utility pole will not create a hazard within a predetermined future time period and is therefore suitable for further use. The specific force required in order to cause the conical projection to penetrate any given wall thickness of such poles may be easily controlled by coordinating the driving spring strength in conjunction with the contour of the conical projection which impacts the pole surface. Thus the present invention is well suited for testing of a wide variety of poles and may be easily adjusted to provide an indication of whether the strength of the pole is above or below any desired predetermined level by merely altering the strength of the driving spring member or alternatively altering the contour of the impacting conical projection. Further, because the testing apparatus of the present invention incorporates a relatively few number of parts, it is relatively inexpensive to manufacture yet is able to offer a high degree of reliability both in terms of operation as well as in terms of consistency between successive tests. Also, even in the event that a portion thereof may suffer a failure, the simple nature of the testing apparatus enables a relatively quick and easy repair to be effected.
Additional advantages and features of the present invention will become apparent from the subsequent description and the appended claims taken in conjunction with accompanying drawings.